Watercraft and electricity generator system for harvesting electrical power for wave motion

ABSTRACT

This disclosure provides improved nautical craft that can travel and navigate on their own. A hybrid vessel is described that converts wave motion to locomotive thrust by mechanical means, and also converts wave motion to electrical power for storage in a battery. The electrical power can then be tapped to provide locomotive power during periods where wave motion is inadequate and during deployment. The electrical power can also be tapped to even out the undulating thrust that is created when locomotion of the vessel is powered by wave motion alone.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 16/213,941, filed,Dec. 7, 2018, issued Feb. 4, 2020 as U.S. Pat. No. 10,549,832, which isa continuation of U.S. Ser. No. 15/635,090, filed Jun. 27, 2017, issuedas U.S. Pat. No. 10,150,546, which application is a continuation of U.S.Ser. No. 14/975,330, filed Dec. 18, 2015, issued as U.S. Pat. No.9,688,373, which is a continuation of U.S. Ser. No. 14/303,470, filedJun. 12, 2014, issued as U.S. Pat. No. 9,353,725 on May 31, 2016, whichis a continuation of U.S. Ser. No. 13/536,935, filed Jun. 28, 2012,issued as U.S. Pat. No. 8,808,041 on Aug. 19, 2014, through which itclaims the priority benefit under 35 U.S.C. § 119(e) of the followingU.S. provisional patent applications:

-   -   U.S. Provisional Patent Application No. 61/502,279:        “Energy-harvesting water vehicle,” filed Jun. 28, 2011;    -   U.S. Provisional Patent Application No. 61/535,116:        “Wave-powered vehicles,” filed Sep. 15, 2011; and    -   U.S. Provisional Patent Application No. 61/585,229: “Retractable        nesting wing racks for wave-powered vehicle,” filed Jan. 10,        2012.

U.S. Ser. No. 13/536,935 also claims the priority benefit of thefollowing patent applications, all filed Mar. 19, 2012.

-   -   International Patent Application No. PCT/US2012/029718 and U.S.        patent application Ser. No. 13/424,239, both entitled        “Autonomous wave-powered substance distribution vessels”    -   International Patent Application No. PCT/US2012/029696 and U.S.        patent application Ser. No. 13/424,170, both entitled        “Wave-powered vessels configured for nesting”; and    -   International Patent Application No. PCT/US2012/029703 and U.S.        patent application Ser. No. 13/424,156, both entitled        “Wave-powered device with one or more tethers.”

The aforelisted priority applications, along with U.S. Pat. Nos.7,371,136; 8,043,133; and published applications US 2008/188150 A1; US2008/299843 A1; and WO/2008/109022 are hereby incorporated herein byreference in their entirety for all purposes.

FIELD OF THE INVENTION

The information disclosed and claimed below relates generally to thefields of vessel motility and power generation. More specifically, itprovides watercraft configured for autonomous operation, harvesting bothlocomotive thrust and electrical power from wave motion.

BACKGROUND OF THE INVENTION

Wave-powered vessels have been described in U.S. Pat. Nos. 7,371,136;8,043,133; and published applications US 2008/188150 A1; US 2008/299843A1; and WO/2008/109022. Exemplary vessels are manufactured and sold byLiquid Robotics, Inc., Sunnyvale Calif., USA under the brand WaveGlider®.

A previously unrelated field of development covers large stationarysystems near shore that use wave motion to generate electrical power forcommunities on land. U.S. Pat. No. 4,134,023 discusses an apparatus forextracting energy from waves on water. U.S. Pat. No. 6,194,815 providesa piezoelectric rotary electrical energy generator. Publishedapplication US 2004/0217597 A1 discusses wave energy converters that usepressure differences. U.S. Pat. No. 3,928,967 is the so-called “Salter'sDuck” patent, an apparatus and method of extracting wave energy. Thestatus and perspectives of wave energy technology is generally reviewedby Clément et al. in Renewable and Sustainable Energy Reviews 6 (5):405-431, 2002.

SUMMARY OF THE INVENTION

This disclosure provides improved technology for manufacturing anddeploying nautical craft that can travel and navigate on their own. Ahybrid vessel is described that converts wave motion to locomotivethrust by mechanical means, and also converts wave motion to electricalpower for storage in a battery. The electrical power can then be tappedto provide locomotive power during periods where wave motion isinadequate and during deployment. The electrical power can also betapped to even out the undulating thrust that is created when locomotionof the vessel is powered by wave motion alone.

One aspect of the invention is a wave-powered vessel that has a buoyantvessel body, a mechanical means for converting movement of the vesselbody caused by wave motion to horizontal thrust; and an electricalgenerator for converting movement of the vessel body caused by wavemotion to electrical power. Converting wave motion to horizontal thrustmay be done in a configuration where an underwater component or swimmeris attached below the vessel body by one or more tethers. In thisconfiguration, the swimmer is weighted to travel in water below thevessel body, and is configured to pull the vessel body by way of thetether. The swimmer has fin surfaces that mechanically provide forwardthrust when actuated by rising and falling of the swimmer in the water.

The on-board electrical generator may comprise a means for convertingvertical movement of the vessel body caused by wave motion to electricalpower, a means for converting horizontal movement of the vessel bodythrough water to electrical power, or both. Shown in the figures is awave-powered vessel where the electrical generator comprises a pistonpowered by a swing arm that moves from a horizontal to a verticalposition in accordance with the vertical movement of the vessel body.The swing arm is mechanically connected to a swimmer weighted to travelin water below the vessel body. Optionally, the swimmer may be adaptedso that motion of the fin surfaces may be dampened to increaseelectrical power generated by the electrical generator.

Another type of electrical generator comprises a rotatory fin or turbinepowered by horizontal movement of the vessel body through the water. Inthis case, the rotatory fin or turbine is adapted to generate electricalpower when rotated in one direction, and to act as a motor providinghorizontal thrust to the vessel through the water when rotated in theopposite direction. Further types of electrical generators forharnessing waves powers are detailed later in this disclosure.

Wave-powered vessels according to this invention typically have anelectrically powered motor to provide horizontal thrust that powers thevessel through the water. There is also a battery configured to storeelectrical power generated by the electrical generator and to feedelectrical power to the motor to provide propulsion. Optionally, thevessel may have one or more solar panels that also supply electricalpower to the battery.

The battery may be used to power an inboard or outboard electrical motorat any time there is reserve electrical power and it is desirable toincrease the sped of the vessel. For example, the battery can power themotor during periods where the motion in each full wave cycle isinadequate to provide sufficient horizontal thrust to the vessel.

Another aspect of the invention is a wave-powered vessel with locomotivethrust powered alternately by wave motion and by electrical power so asto buffer the trust powered by the wave motion. The electrical power issupplied by a battery, which in turn is charged up by a system thatconverts wave motion to electrical power, as already outlined.

Another aspect of this invention is a wave-powered vessel configured fordeployment from shore. The vessel is kept in compact form, and launchedby way of the electric motor to deeper water, whereupon the othercomponents of the vessel are deployed outward and downward. A vessel ofthis nature typically has a buoyant vessel body, a swimmer configured toretract and be secured against the vessel body, one or more tethersconnecting the float to the swimmer, an electrically powered motorconfigured to propel the vessel through the water; and a batterysupplying power to the motor, having sufficient capacity to power thevessel from shore to a location where the swimmer can be deployed.Again, the swimmer is weighted to travel in the water below the vesselbody, and is configured with fins to pull the vessel by way of thetether when actuated by vertical movement.

Such a vessel may also have a releasable tow buoy. The vessel body andthe tow buoy are configured so that the tow buoy may be releasablyhoused within the vessel body while on shore, and pulled behind thevessel body after the vessel is deployed.

The vessels of this invention are ideal for use in autonomous operation(without a human attendant on board). The vessel has electronicsconfigured to sense the geographical location of the vessel. There isalso a microprocessor programmed to determine the vessels currentlocation, and steer the vessel from its current location towards atarget location.

Further aspects of the invention will be evident from the descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows how water moves in roughly circular orbits in waves;

FIG. 1B is a side view of a wave-powered vehicle showing the overalloperation;

FIG. 2 shows an example of an algorithm for directing a vessel towardsor maintaining it at a target position (a geographical location);

FIG. 3 shows the availability of solar power as a function of the annualcycle;

FIG. 4 is a block diagram summarizing how the interaction of powersources can occur;

FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B are side views of a vessel thatillustrates how wave motion can be converted to electrical power;

FIG. 7, FIG. 8A, and FIG. 8B show an example of a vessel that uses wavemotion to generate both locomotive thrust and electrical power fromvessel motion;

FIG. 9 is a graph of hypothetical data that illustrates how storedelectrical power in the battery can be used to power the electric motorand provide propulsion whenever desired; and

FIG. 10 is a perspective view showing how a vessel body and a tow buoymay be configured so that the tow buoy may be releasably housed withinthe vessel body while on shore, and pulled behind the vessel body afterthe vessel is deployed.

DETAILED DESCRIPTION

This invention provides watercraft that derive both locomotive thrustand electrical energy by wave motion. Detailed illustrations of theinvention include a vessel that harvests the power of vertical movementusing tethers attached to a spring-loaded suspension device. Wave energyis converted to potential energy in the springs, which is then used todrive an electricity generator. In another example, the vessel has apropeller that can be driven backwards as a generator when in motion soas produce electrical power. Electrical energy obtained by either ofthese means may be used to power electronics or stored in a battery forlater use. The stored energy can be used to provide propulsion on calmdays when wave action does not in itself provide enough power for thevessel to travel at the desired speed.

Converting Vertical Wave Power to Locomotive Thrust

One feature of the watercraft of this invention is the ability to usewave motion to drive the vessel from place to place across a body ofwater.

Wave motion can be approximated for many purposes as a linearsuperposition of roughly sinusoidal waves of varying wavelength, periodand direction. As a wave moves horizontally along the surface, the wateritself moves in roughly circular orbits of logarithmically decreasingdiameter with depth. This is shown in FIG. 1A. The orbit at the surfacehas a diameter equal to the height of the wave. The orbital diameter atdepth is a function of wave length:H _(y) =H _(s) e ^(−2πy/L)where L is the wave length, H_(s) is the surface wave height and H_(y)is the orbital diameter at depth y below the surface.

Vessels can be configured to exploit the difference in motion betweenH_(s) and H_(y), for example, in the following way. A vessel body ispositioned at or near the surface, and a submerged swimmer or glidercomponent is positioned at depth y, and connected to the vessel body byone or more tethers. As waves lift and lower the float portion, wings orfins on the submerged portion passively rotate so as to convert therelative motion of the surrounding water into forward thrust. Theazimuth of the thrust vector can be directed completely independently ofthe direction of the waves by a rudder at the back of the glider. Thevessel has multiple wings each with a short chord dimension. Thisminimizes lost motion between the up stroke and the down stroke andenables successful conversion of even very small waves into forwardthrust.

FIG. 1B is a side view of a wave-powered vehicle that illustrates thisprinciple. The vehicle comprises a float or vessel body 10 resting onthe water surface, and a swimmer 20 hanging below, suspended by one ormore tethers 30. The float 10 comprises a displacement hull 11 and afixed keel fin 12. The swimmer comprises a rudder 21 for steering andwings or fins 22 connected to a central beam of the rack 23 so as topermit rotation of the wings around a transverse axis within aconstrained range, and provide propulsion.

In still water (shown in the leftmost panel), the submerged swimmer 20hangs level by way of the tether 30 directly below the float 10. As awave lifts the float 10 (middle panel), an upwards force is generated onthe tether 30, pulling the swimmer 20 upwards through the water. Thiscauses the wings 22 of the swimmer to rotate about a transverse axiswere the wings are connected to the rack 23, and assume a downwardssloping position. As the water is forced downward through the swimmer,the downwards sloping wings generate forward thrust, and the swimmerpulls the float forward. After the wave crests (rightmost panel), thefloat descends into a trough. The swimmer also sinks, since it isheavier than water, keeping tension on the tether. The wings rotateabout the transverse axis the other way, assuming an upwards slopingposition. As the water is forced upwards through the swimmer, theupwards sloping wings generate forward thrust, and the swimmer againpulls the float forwards.

Thus, the swimmer generates thrust when both ascending and descending,resulting in forward motion of the entire craft.

Autonomous Navigation

A wave-powered vessel may be configured to navigate across a body ofwater autonomously (without human attendance), and to perform its ownpower management.

Self-directed navigation is possible when the vessel is equipped with ameans of determining the geographical location of the vessel, a meansfor determining direction, a means for steering the vessel, and a meansfor operating the steering so that the vessel travels or stays at atarget location. The steering means is typically a rudder that turnssideways against the water so as to cause the vessel to spin towards anew heading. Alternatively or in addition, it may be a mechanicalarrangement that presses upwards and downwards on opposite sides of thevessel in the manner of an aileron, thereby causing the vessel to rollsideways and attain a new heading. Where the vessel comprises a floatand a swimmer connected by a single tether, it is usual to put thesteering means on the swimmer providing the locomotive power. Inconfigurations having two or more tethers, a rudder may be placed on thefloat, the swimmer, or on the float and the swimmer together.

Electronics to sense the geographical location of a vessel cantriangulate off a series of reference points. Particularly effective isthe global positioning system (GPS), or a similar network of positionaltransmitting sources. The vessel will also usually have an electroniccompass or gyroscope to determine the vessel heading. Positional dataabout the geographical location and the vessel heading is processed in adecision algorithm or programmed microprocessor, which may then providenavigation instructions. Consequently, the steering means adjusts tohead the vessel in accordance with the instructions.

FIG. 2 shows an example of an algorithm for directing a vessel towardsor maintaining it at a target position (a geographical location). Oncethe target position is inputted, it is compared with the currentlocation of the vessel inputted from a GPS receiver. The processorcalculates the proper heading, and compares it with the heading inputtedfrom the compass. The processor then outputs instructions to the rudderservo to adjust the vessel onto the correct heading. For vessels thatare capable of regulating transit speed or locomotive force, theprocessor may also output instructions to adjust the speed (not shown).Measurement and correction by comparison with GPS and compass data isperformed iteratively as the journey continues.

Electrical power is typically needed for the electronics used forself-navigation. This can be supplied by photovoltaic cells located onthe deck of the vessel. For low wind resistance, for low visibility, andto reduce the sensitivity to the direction of the sun, it is best ifthis surface is horizontal. For example, the top deck can be installedwith SunPower™ E20 panels each containing 96 Maxeon™ cells. Understandard conditions (irradiance of 1000 Watts/m², AM 1.5, and celltemperature of 25° C.) six panels produce a total of 1962 Watts.

Converting Wave Movement to Electrical Power

This invention advances the field of wave-powered watercraft byproviding two sources of locomotive power. One is a highly efficientmechanical conversion of wave motion directly to locomotive thrust, asdescribed earlier in this disclosure. The second is conversion of wavemotion to electrical power, which can be stored and used at a latertime. Having the two systems on board provides a number of advantages.

FIG. 3 shows the availability of solar power as a function of the annualcycle, and as a function of time (adapted from MD Ageev, AdvancedRobotics 16(1):43-55, 2002). Depending on the size and efficiency of thephotovoltaic cells, there may be periods when solar power is inadequateto power the electronics on board. A battery system can be used tobuffer and sustain the electronics through diurnal variation, but if thevessel spends long periods in the far north, for example, solar powermay be inadequate. On the other hand, using wave motion for locomotivethrust may be insufficiently reliable at or near the equator or insummer months.

The makers of this invention have discovered that when wave motion ishigh, enough power can be harvested not only to propel the vesselthrough the water, but also to provide ample electrical power. In fact,enough electrical power can be harvested from the waves not only topower the electronics, but also to create an energy supply that canlater be used for locomotion. An electrical generator can be driven byvertical and/or horizontal movement of the vessel caused by the waves.The vessel is configured so that the vertical undulations of the vesselare mechanically coupled to a means of providing horizontal locomotivepower to the vessel (such as a fin or wing rack), and are alsomechanically coupled to a generator of electrical power.

In vessels equipped in this way, other sources of electrical power (likephotovoltaic cells for solar power) are entirely optional—the wavemotion mechanically provides power to drive the vessel through thewater, and also provides electricity to run electronics andmicroprocessors aboard.

When electrical power generated from wave motion and/or from solarpanels is in excess of immediate needs, it can be stored in an on-boardrechargeable battery. The stored electrical power can be used at a latertime to power on-board electronics and microprocessors. It can also beused to power an electrically driven propulsion system, such as anelectric motor coupled to a propeller or turbine. Thus, on calm dayswhen there is insufficient wave motion to drive the vessel at thedesired speed, the battery (optionally in combination with photovoltaiccells) can power the propulsion system. Conversely, the wave generatedelectrical power can be stored for use during periods that are too darkto rely entirely on solar power—for example, at night—and/or tosupplement locomotive thrust.

FIG. 4 is a block diagram summarizing how the interaction of powersources can occur. Sources of power are indicated on the top line;results at the bottom. Wave motion can provide locomotive thrust bymechanical interconnection, such as in a two-part vessel where afloating portion is tethered to a submarine portion. Wave motion canalso power a generator adapted for implementation on a vessel, whichgenerates electricity delivered to a rechargeable battery. Vessel motionthrough the water (a result of propulsion mechanically generated fromthe wave action) can power an electrical generator of its own, whichalso feeds the battery. Solar panels (if present) also provideelectrical power to a battery. Although they may be separate, typicallythe battery for any two or three of these power sources are shared bythe sources that are present.

Electrical power from the battery supplies on-board electronics, such asnavigation equipment, a microprocessor that manages power allocation,and sensors or detectors of various kinds. Electrical power can also betapped at any time it's available to provide vessel proportion: eitherto supplement thrust obtained from the wave motion mechanically, or tosubstitute for mechanical thrust at times when wave motion isinsufficient. As explained below, the electric motor may be the sameapparatus as the electrical generator powered by vessel motion, run inreverse to provide vessel propulsion.

FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B are side views of a vessel thatillustrates how wave motion can be converted to electrical power. Thevessel has been equipped to harvest wave motion for both locomotive andelectrical power. There are two tethers 33 a and 33 b connecting thevessel body 31 to the swimmer 32, fastened to opposite arms 34 a and 34b of a suspension device 37 by way of rotating hinges 35. The arms ofthe suspension are spring loaded to return to a neutral horizontalconfiguration in opposite directions along an axis parallel to thevessel's length, pivoting around a central suspension point 36.

Also shown on the vessel body 31 are a propeller 41 powered by anelectric motor 42, a rudder 43, and an assembly 44 for receiving andtransmitting data and operating instructions that is mounted on the topdeck 45. The configuration can be adapted with more tethers attached tomore link arms that fold forwards and/or backwards, and are mounted onthe vessel body 31 beside, in front, or behind the suspension device 37shown here.

FIG. 5A superimposes three images showing what happens when the vesselbody 31 is lifted by a wave. At the starting position, the suspensiondevice 37 is configured in the neutral position with arms 34 a and 34 bhorizontally positioned in opposite directions. As the wave lifts thevessel body M, it pulls the swimmer 32 upwards. However, the density ofwater slows the upward movement of the swimmer 32, thereby pulling thearms 34 a and 34 b of the suspension device 37 downwards. This loads thespring on each arm with potential energy.

FIG. 5B superimposes three images showing what happens as the vesselapproaches the crest of the wave. The upwards motion of the vessel body31 slows, but the swimmer 32 still travels upwards due to the tension inthe arms when they were being pulled downward. As the swimmer 32continues upwards to a point where the arms 34 a and 34 b resume theneutral horizontal position, the potential energy in the suspensiondevice 37 is released, and can be captured by a generator means thatconverts the potential energy in the spring into electrical power.

FIG. 6A superimposes three images of the configuration of the suspensiondevice 37 as the potential energy is released. In this example, the twotether winches 33 a and 33 b pivotally mounted 35 to the ends oflink-arms 34 a and 34 b drive a piston: specifically, a linear hydrauliccylinder 38, which in turn creates pressure to drive a hydraulic turbinegenerator (not shown). For simplicity the hydraulic cylinder 38 is shownhere attached to only one of the link arms 34 a, although more typicallythere is another hydraulic cylinder attached to the other link arm 34 b.The link arms 34 a and 34 b could package nicely in the center spanstructure without protruding above the deck 45 of the vessel body 31.Optionally, the link arms 44 a and 44 b can be configured to lock in theneutral horizontal position during times where all of the wave energy isneeded for thrust, or when electric generation is not necessary.

FIG. 6B provides a detail of the action of the hydraulic cylinder 38during a cycle of movement of the link arm 34 a from the neutralhorizontal position to the vertical tending spring loaded position asthe swimmer is pulled upwards by the vessel body 31 as the wave peaks.When the link arms are in the neutral position, the hydraulic cylinderis extended 39 a, and is pushed together 39b into a compressed position39 c as the link arm 34 a descends towards the vertical. When the linkarm 34 a returns to the horizontal position as the wave troughs, thehydraulic cylinder returns to the extended position 39 a, completing thecycle.

The arrangement shown in these figures may be adjusted to the user'sliking to fit a particular installation. The swing arm system shown inFIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B may be placed on the swimmerrather than on the float. The link arms are pivotally mounted at theproximal end towards the upper surface of the swimmer, and are springloaded to assume a horizontal neutral position. The tether is attachedto the distal end of the arm, and connects to the float above. Wavemotion again stretches the distance between the float and the tether,but in this case the link arms are pulled into an upwards orientation,creating potential energy in the spring that can be converted toelectrical power.

Whether mounted on the float or the swimmer, the electrical powergeneration system may harvest the up and down motion of the link arms bya suitable arrangement that ultimately results in a mechanical forceturning conductive wire or bar within a magnetic field, or turning amagnet through a conductor. Included are mechanical arrangements thatresult directly in rotatory motion (such as a rotating axle), or aback-and-forth action (such as a liquid or gas filled piston) that canbe converted mechanically into rotatory motion.

The electrical power generation system shown in FIG. 5A, FIG. 5B, FIG.6A, and FIG. 6B are provided by way of an example of how such a systemmay be implemented with high conversion efficiency. The example is notmeant to limit practice of the claimed invention except where explicitlyindicated. Other systems for harnessing electricity from wave power on amoving vessel may be adapted from stationary on-shore technology nowdeployed or under development.

Electrical power generating systems may be configured to harnessvertical oscillation of the water surface in a wave cycle, or horizontalmovement of the wave peaks, or a combination of the two. By way ofillustration, a system that harvests electrical power from verticalmovement can comprise a tube that floats vertically in the water andtethered to the vessel. The tube's up-and-down bobbing motion is used topressurize water stored in the tube below the surface. Once the pressurereaches a certain level, the water is released, spinning a turbine andgenerating electricity. In another illustration, an oscillating watercolumn drives air in and out of a pressure chamber through a Wellsturbine. In a third illustration, the power generating system comprisesa piston pump secured below the water surface with a float tethered tothe piston. Waves cause the float to rise and fall, generatingpressurized water, which is then used to drive hydraulic generators.

To harvest horizontal wave movement, the electrical power generatingsystem may comprise one or more large oscillating flaps positioned tocatch waves as they go by. The flap flexes backwards and forwards inresponse to wave motion, which in turn drives pistons that pump seawaterat high pressure through a pipe to a hydroelectric generator. Anotherimplementation comprises a series of semi-submerged cylindrical sectionslinked by hinged joints. As waves pass along the length of theapparatus, the sections move relative to one another. The wave-inducedmotion of the sections is resisted by hydraulic cylinders, which pumphigh pressure water or oil through hydraulic motors via smoothinghydraulic accumulators. The hydraulic motors drive electrical generatorsto produce electrical power.

Converting Horizontal Movement of the Vessel to Electrical Power

Another way of converting wave motion to electrical power is a two-stepprocess. The first step is to use the wave motion to create locomotivethrust, thereby causing the vessel to move through the water. The secondstep is to harvest the movement of the water about the vessel resultingfrom the locomotion, and convert it to electrical power.

FIG. 7, FIG. 8A, and FIG. 8B show an example of a vessel that uses wavemotion to generate both locomotive thrust and electrical power fromvessel motion. In this example, the swimmer or wing-rack is tethered tothe buoy or vessel body by a foreward and aft tether with a winch foradjusting the length of tether that is deployed. As the buoy moves upand down with the waves, the swimmer rack has wings that translate thevertical movement into transverse locomotive movement. The wing-rackthen pulls the vessel body as directed by the rudder under control ofthe microprocessor.

The electrical system shown here comprises upward facing solar panels,providing an auxiliary source of electrical power. The power module forgenerating electricity is shown in detail in FIG. 8B. The modulecomprises rechargeable batteries, a rotating magnet conductorarrangement that plays the role of both motor and generator, and a thirdcomponent that plays the role of both propeller and turbine. As shown inFIG. 7, when there is an abundance of wave power, the wings on theswimmer generate thrust or locomotive power to move the vessel forward.As the waves power the vessel through the water, the propeller is turnedbackwards, applying torque to the motor so as to generate electricalpower for storage in the battery. When there is an absence of windpower, or when the wing rack is retracted into the vessel body, thebatteries or solar panel powers the motor, which turns the propeller soas to provide locomotive power.

The power module is shown in FIG. 8A secured to one side of a catamarantype float. This can be varied to secure the power module for example tothe other side, to the middle of a float with a central keel, or to theside rails or middle spine of the swimmer. Two or more power modules canbe used, secured for example to both sides of a catamaran type float, orto a float and swimmer together in any combination.

In the example shown, the hull type is a displacement catamaran, whichhas the advantage of being very efficient below the hull speed, and canbe powered up to 3 times faster than the hull speed with minimal wake.It has six 325 watt SunPower panels for almost 2000 watts peak solarpower collection. It also has two Tesla-sized lithium ion battery packshoused in cylindrical power modules that are pressure tolerant to 200 m.These packs each have roughly 7000 cells totally 25 kWh of energy. Thepower modules are 12.75 inches in diameter—the same as a Remus 600 or aBlueFin 12D AUV.

Balancing Between Locomotive Thrust and Electrical Power Generation

In some implementations of the invention, the various power harvestingsystems on a vessel may be configured to be regulated so as toprioritize delivery of power from wave motion to locomotive thrust orelectricity generation in the desired proportion.

The electrical power generating system may be configured to lock out orvariably dampen movement of the components that convert the wave motionto rotatory motion, and hence to electricity. For example, the link armsystem shown in FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B may be designedso that the link arms may be secured by a clamp or other means in thehorizontal neutral position. This effectively locks out the powergenerating system in favor of the wave-powered propulsion system, whichmay be desirable when the wave motion is not in excess of what isrequired to propel the vessel at the intended speed, and/or whenelectrical power is not needed (for example, when the battery is chargedto full capacity). In a variation of this system, the damping isvariable, so that the proportion of wave motion used for electricalpower generation may be precisely adjusted.

Conversely, the wave-powered propulsion system may be configured to lockout or variably dampen movement of the components that convert the wavemotion to thrust. For example, the wings or fins shown in FIG. 1B may bedesigned so that they may be secured in a neutral position. Thiseffectively locks out the propulsion system in favor of the electricalpower generating system, which may be desirable when the wave motion iswell in excess of what is required to propel the vessel at the intendedspeed, and/or when electrical power is needed in greater abundance topower on-board electronics and/or recharge the battery. In a variationof this system, the damping is variable, so that the proportion of wavemotion used for locomotive thrust may be precisely adjusted.

Besides adjusting use of the wave motion between thrust and electricitygeneration, a variable damping system on the propulsion system may havea further benefit: namely, to regulate speed of the vessel depending onthe amount of wave motion currently available, and the desired targetlocation. For example, when it is desired that the vessel stay inposition at its current location, the propulsion regular and rudder maybe caused assume a direction and speed that exactly compensates for thenet effect of underlying current, wind, and horizontal wave forceaffecting the vessel's position. This effectively secures the vessel atits current GPS location, and saves the vessel from having to travel incircles to maintain its position.

Thus, either the propulsion system, or the electrical power generatingsystem, or both may be configured with a lock out or variable dampingarrangement to adjust the priority between the two systems.

Where such regulation systems are installed, they may be controlled byan on-board microprocessor programmed to determine the appropriatepriority between locomotion and electrical power generation, and then toregulate the damping or lockout devices on each system accordingly. Themicroprocessor may be programmed to take into account such factors asvertical wave motion, latitude (determined by GPS), temperature, otherweather factors, battery level, distance from the intended targetlocation, amount of available solar power, time of day, payload, sensordata, and operating parameters programmed into or transmitted to themicroprocessor.

Alternating Locomotive Thrust from Wave Motion and an Electrical Motorto Buffer Vessel Speed

Stored electrical power in the battery can be used to power the electricmotor and provide propulsion whenever desired. Besides powering themotor during periods when wave motion is quiescent, it can be used on anongoing basis to buffer the trust powered by the wave motion.

FIG. 9 is a graph of hypothetical data that illustrates how this mightwork. Mechanisms that convert wave motion into locomotive power bygradually pressurizing a gas or a liquid may provide fairly uniformthrust. However, other mechanisms result in undulations in thrust thatoccur once or twice per wave cycle. For example, in a configurationwhere a wing rack is tethered beneath a float (as in FIG. 1B), themechanism provides forward thrust while the rack is travelling upwardsor downwards in the wave cycle. When the wave is peaking or at itsnadir, tension on the tethers is fairly constant, and forward thrust isminimal. Thus, in a single wave cycle (as shown in FIG. 9), forwardthrust peaks twice.

In many uses of a wave-powered vessel, the undulations are of littleconsequence. However, there are instances in which a constant speed (andthus relatively constant thrust) is desirable: for example, when usingsensors that comprise streamers flowing backwards from the vessel. Theundulations in thrust obtained by mechanical conversion can be bufferedby powering the electrical motor in an undulating pattern of the samefrequency but essentially out of phase. In this manner, thrust frommechanical conversion and thrust from the electric motor alternate, sothat the combined locomotive thrust is buffered to a more consistentlevel. The pattern of power to the electric motor may be controlled byan on board microprocessor programmed to detect the wave cycle, predictthe undulations in mechanically derived locomotive thrust, andsynchronize the electric motor out of phase to compensate.

Watercraft Configured for Self-Deployment

Another advantage of the hybrid powered vehicles of this invention isthat in many instances they may be deployed directly from shore. Thissaves the trouble and expense of hiring a special vessel and crew to dothe deployment in deep water. Instead, the components of the vessel arekept bound together, and the electric motor powers the vessel to deepwater for full deployment.

For example, a wave-powered vessel configured for deployment from shoremay comprise a buoyant vessel body, a swimmer configured to retract andbe secured against the vessel body, one or more tethers connecting thefloat to the swimmer, an electrically powered motor configured to propelthe vessel through the water, and a battery supplying power to themotor, having sufficient capacity to power the vessel from shore to alocation where the swimmer can be deployed. The battery is charged upbefore launch, and the swimmer is kept secured to the float. Theelectric motor takes the vessel to deep water, and then the tethers arelet out to deploy the swimmer to its operative position below thefloat—either automatically, or by remote control. After deployment, thebattery can be recharged on an ongoing basis using the electrical powergenerating systems aboard the vessel.

FIG. 10 provides a further illustration. Some projects with wave poweredvessels require the vessels to take a substantially massive payload. Ifkept aboard the float or the swimmer, the payload could impair verticalmovement, and thus reduce efficiency of the vessel for converting wavemotion to thrust and electrical power. Typically, the payload is towedin a container or platform referred to as a “tow buoy” behind the floator the swimmer, either on or below the water surface. However, deployingthe vessel and the tow buoy separately from shore is difficult.

The figure shows how the vessel body and the tow buoy may be configuredso that the tow buoy may be releasably housed within the vessel bodywhile on shore, and pulled behind the vessel body after the vessel isdeployed. The refinements shown include rollers to guide the tow buoy upone or more complementary ramps inside the float. To transport thevessel to the launch site, the tow buoy is positioned securely insidethe float, and the tethers connecting the wing racks to the float areretracted so that the wing racks nest securely to the bottom of thefloat. Following launch, the precharged battery powers the vessel todeep water, whereupon the wing racks are deployed downward, and the towbuoy is deployed out the back of the float so as to be towed by thefloat without impairing the float's vertical movement due to wavemotion.

Use of Wave-Powered Watercraft

The hybrid wave-powered vessels of this invention can be manufactured,sold, and deployed for any worthwhile purpose desired by the user. Forexample, the vessels can be used to survey and monitor regions of theocean or other bodies of water, including the chemistry of water andair, weather, and marine life. The vessels can be used to relay signalsfrom sensors under the water or on other vessels to a data processingcenter. They can be used to monitor activities on shore, and thebehavior of other watercraft. They can also be used to distributesubstances into the ocean from the vessel body or from a tow buoy.

Sensors and related equipment that may be used include one or more ofthe following in any suitable combination:

-   -   Sensors for gas concentrations in air or water    -   Heat flux sensors    -   Meteorological sensors: wind speed & direction, air temperature,        solar intensity, rain fall, humidity, pressure    -   Physical oceanography sensors; wave spectrum & direction,        current sensors, CTD profiles    -   Micro-organism counts and classification through water sampling        and vision systems    -   Fish and wildlife tracking by acoustic tag detection, such as        those manufactured by Vemco    -   FAD structures to provide shade and attract marine life    -   Acoustic sensors for active or passive detection and        classification of marine wildlife. For example, hydrophone for        listening to whales, or active sonar for fish counts    -   Chemical sensors to detect the concentration of a substance        being released by the vessel

Equipment installed on a vessel of this invention to facilitate datacollection may include a means for obtaining sensor data at variabledepths. This can be achieved using a winch system to lower and raisesensors mounted on a heavier-than-water platform. Another option is atow buoy mounted with sensors, with servo-controlled elevator fins toalter the pitch of the tow body, thereby controlling its depth whilebeing pulled. The vessel may also have data storage systems and amicroprocessor programmed to process and interpret data from thesensors, either integrated into the location and navigation processingand control system on the vessel, or as a stand-alone microprocessorsystem.

Watercraft of this invention equipped with sensors and/or payloads havea variety of sociological and commercially important uses. Such usesinclude fertilizing plankton, feeding fish, sequestering carbon from theatmosphere (PCT/US2012/029718), conducting seismic surveys (US2012/0069702 A1) or prospecting for new sources of minerals or fuel oil.

Glossary

The terms “vessel”, “watercraft”, and sea going “vehicle” are usedinterchangeably in this disclosure and previous disclosures to refer toa nautical craft that can travel across and about any body of water ator near the surface.

A “wave-powered” vessel is a vessel that derives at least a majority ofits power for locomotion from motion of the water in relation to thesurface. Optionally, the vessel may also derive power from solar energyand other natural sources, and/or man-made sources such as batteries andliquid fuel powered engines. In this context, a “wave” is any upward anddownward motion of the surface of a body of water at a point ofreference (such as the center of floatation of a vessel).

A “vessel body” or “float” is a component of a vessel that travels on ornear the surface of the water. It may have its own source of locomotivepower and/or rely on being pulled by a submarine component. It is madebuoyant by having a density (including enclosed air pockets and upwardopening cavities) that is

A “swimmer”, “pod”, “submarine component”, “sub”, “glider” or “wingrack” is a component of a vessel that travels below the surface of thewater and below the vessel body, to which it provides locomotive poweror propulsion. The swimmer is heavier than water, so as to traveldownwards through the water to the extent allowed by the tethers and thevessel body and suspension systems to which the tethers are attachedabove. It is typically equipped with a plurality of “fins” or “wings”that rotate upwards or downwards around an axle transverse to thedirection of travel. This disclosure generally refers to vessels havingsingle swimmers or wing racks. However, vessels may be configured withmultiple swimmers, typically joined to the same two or more tethers atdifferent depths, each providing locomotive thrust in response to waveaction, and optionally configured for nesting when retracted(PCT/US2012/029696). Thus, all the aspects of this invention derivingwave power from a swimmer includes or can be adapted mutatis mutandis toinclude two, three, or more than three swimmers or wing racks.

An “autonomous” vessel is a vessel that is designed and configured totravel across a body of water without needing a human on board or inconstant active control at a remote location. It has a self-containedsource of locomotive power. Navigation is controlled, either by acombination of sensors, electronics, and microprocessors aboard or at aremote location and in wireless communication with the vessel. Thevessel may also be programmed to manage the ratio of locomotive powerderived mechanically from wave action, and from an electric motor. Itmay also be programmed to control dampening of the action of fins on theswimmer.

A “tow buoy” is a storage container or equipment platform that is towedbehind a vessel, attached either the float or the swimmer, and travelingon or below the water surface. The term does not necessarily indicatethat the container or platform has a degree of buoyancy.

A “microprocessor” or “computer processor” on a vessel or control unitof the invention inputs data, processes it, and then provides outputsuch as data interpretation or instructions to direct the activity ofanother apparatus or component. For vessels or units that have differentdata sets for processing in different ways, the microprocessor for eachalgorithm may be separate, but more commonly they are a singlemicroprocessor configured and programmed to process each the differentdata sets with the corresponding algorithms when it is appropriate

The wave-powered vessels of this invention may be organized in fleets oftwo or more that interact with each other and/or with a central controlunit. The terms “control unit”, “central control unit” and “controlcenter” are used interchangeably to refer to an electronic assembly orcombination of devices that receives information about one or moreconditions of the water, the weather, or other aspects of theenvironment at one or more locations, makes decisions about where it isappropriate to distribute fertilizer or another substance from one ormore distribution vessels, and sends instructions to the vessels in thefleet accordingly. The control unit may be placed anywhere on shorewithin range to receive and transmit data and instructions, or it may beaboard one of the vessels in the fleet, optionally integrated with themicrocircuitry of that vessel.

For all purposes in the United States of America, each and everypublication and patent document cited herein is incorporated herein byreference as if each such publication or document was specifically andindividually indicated to be incorporated herein by reference.

While the invention has been described with reference to the specificembodiments, changes can be made and equivalents can be substituted toadapt to a particular context or intended use, thereby achievingbenefits of the invention without departing from the scope of what isclaimed.

What is claimed is:
 1. A wave powered vessel, comprising: a buoyantvessel body, comprising a propeller; a swimmer body, mechanicallycoupled to the vessel body, the swimmer body comprising a plurality ofwings having wing surfaces; a forward tether and an aft tether,tethering the buoyant vessel body and the swimmer body; wherein theplurality of wings translate at least a portion of vertical motionbetween the buoyant vessel body and the swimmer body into transverselocomotive movement of the wave powered vessel; a motor, mechanicallycoupled to the propeller, the motor for: turning the propeller in afirst direction to provide locomotive power; and generating electricalpower from at least a portion of the transverse locomotive movement ofthe wave powered vessel translated by the wings from the at least theportion of the vertical motion between the buoyant vessel body and theswimmer body.
 2. The wave powered vessel of claim 1, wherein: theswimmer body and the plurality of wings comprise a deployedconfiguration, and a retracted configuration; and the motor generateselectrical power from the transverse locomotive movement of the wavepowered vessel in the deployed configuration.
 3. The wave powered vesselof claim 1, wherein: the wing surfaces are variably damped, the variabledamping selected to control a proportion of the at least the portion ofthe movement of the vessel body relative to the swimmer body convertedto locomotive thrust to the at least the portion of the movement of thevessel body relative to the swimmer body converted to electrical power.4. The wave powered vessel of claim 3, wherein the proportion of the atleast the further portion movement of the vessel body relative to theswimmer body converted to the locomotive thrust to the at least theportion of the movement of the vessel body relative to the swimmer bodyconverted to electrical power is controlled to regulate a speed of thevessel.
 5. The wave powered vessel of claim 3, wherein the proportion ofthe at least the further portion movement of the vessel body relative tothe swimmer body converted to the locomotive thrust to the at least theportion of the movement of the vessel body relative to the swimmer bodyconverted to electrical power is controlled to retain the vessel at aposition.
 6. The wave powered vessel of claim 1, further comprising abattery, coupled to the motor for storing the generated electricalpower.
 7. The wave powered vessel of claim 1, wherein the aft tethercomprises a winch, for adjusting a length of the aft tether.
 8. A methodof powering a wave powered vessel comprising a buoyant vessel bodymechanically coupled to a swimmer body having a plurality of wingshaving wing surfaces by at least one tether, comprising: mechanicallyconverting, with a generating system, at least a portion of a movementof the vessel body relative to the swimmer body caused by wave motioninto electrical power, comprising: (a) generating vertical motionbetween the buoyant vessel body and the swimmer body; (b) translating,using the wings, at least a portion of the vertical motion between thebuoyant vessel body and the swimmer body into transverse locomotivemovement of the wave powered vessel; and (c) generating electrical powerfrom at least a portion of the transverse locomotive movement of thewave powered vessel translated by the wings from the at least theportion of the vertical motion between the buoyant vessel body and theswimmer body by driving a propeller coupled to a motor using thetransverse locomotive movement of the wave powered vessel.
 9. The methodof claim 8, wherein: the swimmer body and plurality of wings comprise adeployed configuration, and a retracted configuration; and the methodfurther comprises: placing the wave powered vessel in the deployedconfiguration before performing steps (a)-(b); and placing the wavepowered vessel in the retracted configuration before performing step(c).
 10. The method of claim 9, wherein only a portion of the transverselocomotive movement of the wave powered vessel translated by the wingsgenerates electrical power.
 11. The method of claim 10, wherein: thewing surfaces are variably damped, the variable damping selected tocontrol a proportion of the at least the portion of the movement of thevessel body relative to the swimmer body converted to locomotive thrustto the at least the portion of the movement of the vessel body relativeto the swimmer body converted to electrical power.
 12. The method ofclaim 11, wherein a proportion of the at least the further portion ofthe movement of the vessel body relative to the swimmer body convertedto the locomotive thrust to the at least the portion of movement of thevessel body relative to the swimmer body converted to electrical poweris controlled to regulate a speed of the vessel.
 13. The method of claim12, wherein: the proportion of the at least the further portion of themovement of the vessel body relative to the swimmer body converted tothe locomotive thrust to the at least the portion of the movement of thevessel body relative to the swimmer body converted to electrical poweris controlled to retain the vessel at a position.
 14. The method ofclaim 8, further comprising: (e) storing the generated electrical powerin a battery.
 15. The method of claim 14, further comprising: (f)propelling the vessel using the stored electrical power, the motor andthe propeller.
 16. A wave powered vessel, comprising: a buoyant vesselbody; a swimmer body, mechanically coupled to the vessel body, theswimmer body comprising wings having wing surfaces; a generating systemstructured to convert at least a portion of movement of the vessel bodyrelative to the swimmer body caused by wave motion into electricalpower, the generating system comprising: means for translating at leasta portion of vertical motion between the buoyant vessel body and theswimmer body into transverse locomotive movement of the wave poweredvessel; and means for generating electrical power from at least aportion of the transverse locomotive movement of the wave powered vesseltranslated by the wings from the at least the portion of the verticalmotion between the buoyant vessel body and the swimmer.
 17. The wavepowered vessel of claim 1, wherein: the swimmer body and plurality ofwings comprise a deployed configuration, and a retracted configuration;and means for generating electrical power generates electrical powerfrom the transverse locomotive movement of the wave powered vessel inthe deployed configuration.
 18. The wave powered vessel of claim 17,wherein: the wing surfaces are variably damped, the variable dampingselected to control a proportion of the at least the portion of themovement of the vessel body relative to the swimmer body converted tolocomotive thrust to the at least the portion of the movement of thevessel body relative to the swimmer body converted to electrical power.19. The wave powered vessel of claim 18, wherein the proportion of theat least the further portion movement of the vessel body relative to theswimmer body converted to the locomotive thrust to the at least theportion of the movement of the vessel body relative to the swimmer bodyconverted to electrical power is controlled to regulate a speed of thevessel.
 20. The wave powered vessel of claim 18, wherein the proportionof the at least the further portion movement of the vessel body relativeto the swimmer body converted to the locomotive thrust to the at leastthe portion of the movement of the vessel body relative to the swimmerbody converted to electrical power is controlled to retain the vessel ata position.